MybatisPlus简单使用CRUD

一.结构图

创建的springboot工程

数据库

二.代码

pom.xml

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.2.1.RELEASE
         
    
    com.ding
    demomptest
    0.0.1-SNAPSHOT
    demomptest
    Demo project for Spring Boot
    
        1.8
    
    
        
            org.springframework.boot
            spring-boot-starter
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
        


        
        
            com.baomidou
            mybatis-plus-boot-starter
            3.3.1
        

        
        
            mysql
            mysql-connector-java
        
        
        
            org.projectlombok
            lombok
            true
        

    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

config

package com.ding.demomptest.config;

import com.baomidou.mybatisplus.extension.plugins.OptimisticLockerInterceptor;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * @Description TODO
 * @Author 丁帅帅
 * @Date 21/09/19 10:13
 * @Version 1.0
 */
@Configuration
@MapperScan("com.ding.demomptest.mapper")
public class MpConfig {
    /**
     * 乐观锁插件
     */
    @Bean
    public OptimisticLockerInterceptor optimisticLockerInterceptor() {
        return new OptimisticLockerInterceptor();
    }

    /**
     * 分页插件
     */
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        return new PaginationInterceptor();
    }

}

entity

package com.ding.demomptest.entity;

import com.baomidou.mybatisplus.annotation.*;
import lombok.Data;

import java.util.Date;

/**
 * @Description TODO
 * @Author 丁帅帅
 * @Date 21/09/18 20:54
 * @Version 1.0
 */
@Data
public class User {
    @TableId(type = IdType.ASSIGN_ID)
    private Long id;
    private String name;
    private Integer age;
    private String email;

    @TableField(fill = FieldFill.INSERT)
    private Date createTime;  //create_time

    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Date updateTime; //update_time

    @Version
    @TableField(fill = FieldFill.INSERT)
    private Integer version;

    @TableLogic
    @TableField(fill = FieldFill.INSERT)
    private Integer deleted;
}

handle

package com.ding.demomptest.handle;

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;

import java.util.Date;

/**
 * @Description TODO
 * @Author 丁帅帅
 * @Date 21/09/19 10:12
 * @Version 1.0
 */
@Component
public class MyMetaObjectHandler implements MetaObjectHandler {

    //mp执行添加操作，这个方法执行
    @Override
    public void insertFill(MetaObject metaObject) {
        this.setFieldValByName("createTime",new Date(),metaObject);
        this.setFieldValByName("updateTime",new Date(),metaObject);
        this.setFieldValByName("version",1,metaObject);
        this.setFieldValByName("deleted",0,metaObject);
    }

    //mp执行修改操作，这个方法执行
    @Override
    public void updateFill(MetaObject metaObject) {
        this.setFieldValByName("updateTime",new Date(),metaObject);
    }
}

mapper

package com.ding.demomptest.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.ding.demomptest.entity.User;
import org.springframework.stereotype.Repository;

/**
 * @Description TODO
 * @Author 丁帅帅
 * @Date 21/09/18 20:54
 * @Version 1.0
 */
@Repository
public interface UserMapper extends BaseMapper {
}

resources

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/mybatisplus?serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=root

#mybatis日志
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

test

package com.ding.demomptest;

import com.ding.demomptest.entity.User;
import com.ding.demomptest.mapper.UserMapper;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@SpringBootTest
class DemomptestApplicationTests {

    @Autowired
    private UserMapper userMapper;


   //修改
    @Test
    public void testUpdate(){
        User user = new User();
        user.setId(1L);
        user.setName("Jeff");
        int count = userMapper.updateById(user);
        System.out.println(count);
    }
    //多个id批量查询
    @Test
    public void testSelect1() {
        List users = userMapper.selectBatchIds(Arrays.asList(1, 2, 3));
        System.out.println(users);
    }

    //简单条件查询
    @Test
    public void testSelect2(){
        Map columnMap = new HashMap<>();
        columnMap.put("name","Jack");
        columnMap.put("age",20);
        List users = userMapper.selectByMap(columnMap);
        System.out.println(users);
    }

    //添加
    @Test
    public void testAdd() {
        User user = new User();
        user.setName("李四");
        user.setAge(20);
        user.setEmail("1243@qq.com");
        user.setDeleted(0);
        int insert = userMapper.insert(user);
        System.out.println(insert);
    }
    //测试乐观锁
    @Test
    public void testOptimisticLocker() {
        //根据id查询
        User user = userMapper.selectById(1439422114023026690L);
        //修改
        user.setName("王二");
        userMapper.updateById(user);
    }

    //根据id删除
    @Test
    public void testDeleteId() {
        int rows = userMapper.deleteById(1439421384058949634L);
        System.out.println(rows);
    }

}

原文：https://www.cnblogs.com/dss-99/p/15311087.html